Microglia are the main non-neuronal cells in the central nervous system that have important roles in brain development and functional connectivity of neural circuits.In brain physiology,highly dynamic microglial proce...Microglia are the main non-neuronal cells in the central nervous system that have important roles in brain development and functional connectivity of neural circuits.In brain physiology,highly dynamic microglial processes are facilitated to sense the surrounding environment and stimuli.Once the brain switches its functional states,microglia are recruited to specific sites to exert their immune functions,including the release of cytokines and phagocytosis of cellular debris.The crosstalk of microglia between neurons,neural stem cells,endothelial cells,oligodendrocytes,and astrocytes contributes to their functions in synapse pruning,neurogenesis,vascularization,myelination,and blood-brain barrier permeability.In this review,we highlight the neuron-derived“find-me,”“eat-me,”and“don't eat-me”molecular signals that drive microglia in response to changes in neuronal activity for synapse refinement during brain development.This review reveals the molecular mechanism of neuron-microglia interaction in synaptic pruning and presents novel ideas for the synaptic pruning of microglia in disease,thereby providing important clues for discovery of target drugs and development of nervous system disease treatment methods targeting synaptic dysfunction.展开更多
The rapidly advancing Convolutional Neural Networks(CNNs)have brought about a paradigm shift in various computer vision tasks,while also garnering increasing interest and application in sensor-based Human Activity Rec...The rapidly advancing Convolutional Neural Networks(CNNs)have brought about a paradigm shift in various computer vision tasks,while also garnering increasing interest and application in sensor-based Human Activity Recognition(HAR)efforts.However,the significant computational demands and memory requirements hinder the practical deployment of deep networks in resource-constrained systems.This paper introduces a novel network pruning method based on the energy spectral density of data in the frequency domain,which reduces the model’s depth and accelerates activity inference.Unlike traditional pruning methods that focus on the spatial domain and the importance of filters,this method converts sensor data,such as HAR data,to the frequency domain for analysis.It emphasizes the low-frequency components by calculating their energy spectral density values.Subsequently,filters that meet the predefined thresholds are retained,and redundant filters are removed,leading to a significant reduction in model size without compromising performance or incurring additional computational costs.Notably,the proposed algorithm’s effectiveness is empirically validated on a standard five-layer CNNs backbone architecture.The computational feasibility and data sensitivity of the proposed scheme are thoroughly examined.Impressively,the classification accuracy on three benchmark HAR datasets UCI-HAR,WISDM,and PAMAP2 reaches 96.20%,98.40%,and 92.38%,respectively.Concurrently,our strategy achieves a reduction in Floating Point Operations(FLOPs)by 90.73%,93.70%,and 90.74%,respectively,along with a corresponding decrease in memory consumption by 90.53%,93.43%,and 90.05%.展开更多
Prunusmumehas high ornamental value,and its maintenance and management should be more meticulous,with pruning being an important task.Pruning can make P.mume more robust,reduce the occurrence of diseases and pests,mai...Prunusmumehas high ornamental value,and its maintenance and management should be more meticulous,with pruning being an important task.Pruning can make P.mume more robust,reduce the occurrence of diseases and pests,maintain a good shape,and promote more flowering,further improving its ornamental value.The difficulty of pruning lies in flexibly adopting suitable pruning methods according to the time of the tree,which requires understanding the impact of pruning operations on the growth and flowering of P.mume,as well as some techniques in pruning operations.This paper introduces the botanical characteristics of P.mume,common pruning methods and achievable effects of P.mume,and suitable time for using various methods,and analyzes the possible consequences and reasons of some incorrect operations.Moreover,corresponding correct practices are provided,which can provide reference for standardized pruning of P.mume,thereby reducing or avoiding losses caused by improper operation.展开更多
To determine the correlations between the tree structuresof Fuji apple with different pruning modes and each factor, the data about 3 tree structures which were free spindle short shoot, free spindle long shoot and sl...To determine the correlations between the tree structuresof Fuji apple with different pruning modes and each factor, the data about 3 tree structures which were free spindle short shoot, free spindle long shoot and slenderspindle short shoot in Xingtang County of Hebai Province were investigated, then by SPSS anal- ysis, the correlations between the taperingness and each growth factor of inserted small branch were compared. The results showed that the taperingness of central trunk of free spindle dwarf-shoot Fuji apple treeshad negative correlations with each factor of inserted small branch, while the taperingness of central trunk of free spin- dle long-shoot Fuji apple treeshad positive correlations with each factor of inserted small branch, the taperingness of central trunk of slenderspindle short-shootFuji ap- ple treeshad negative correlation with total thickness of inserted small branch, but had positive correlations with other factors. This study can provide a scientifictheo- retical basis for the pruning technology of high-density planting trees grafting by dwarfing self-rooted rootstock.展开更多
To determine the correlation between the stem taperingness and central shaft by free spindle pruning mode on different apple cultivars, the central shaft growth data of three cultivars of free spindle short shoot "F...To determine the correlation between the stem taperingness and central shaft by free spindle pruning mode on different apple cultivars, the central shaft growth data of three cultivars of free spindle short shoot "Fuji", free spindle long shoot "Fuji", free spindle "Huaguan" were investigated in Xingtang County of Hebei Province by SPSS analysis. The results showed that the stem taperingness on free spindle short shoot "Fuji" was in negative correlation with central shaft, but the correlation was not significant. While the stem taperingness on free spindle long shoot "Fuji" was in positive correlation with central shaft, but the correlation was not significant either. The stern taperingness on free spindle "Huaguan" was in negative correlation with central shaft, and the correlation between the stem taperingness and the central shaft total length was significant at the level of 0.01. The results.provided scientific theoretical basis for guiding the dwarfing rootstocks close planting apple tree pruning technology.展开更多
In the Yangtze River region, thepepper long-season cultivation needs oversummer pruning. Inorder to study the effects of different pruning treatments on growth of over-summer grown pepper, three differentpruning treat...In the Yangtze River region, thepepper long-season cultivation needs oversummer pruning. Inorder to study the effects of different pruning treatments on growth of over-summer grown pepper, three differentpruning treatments were applied to pepper seedlings, such as treatment one(re-growth pruning), treatment two(four stems) and treatment three(multi-stem pruning) with no pruning as control(CK).The results showed that themulti-stem pruning treatment enabling the plant to maintain the good plant type for high yield and reduce thevirus disease to improve the marketability of pepper fruits, compared with the other two pruning treatments;andthe yield and economic benefit were increased by 15.8% and 19%, compared with the control, respectively. Ingeneral the multi-stem pruning was the best for over-summer pepper cultivation.展开更多
Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized...Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized as a water-saving method that can reduces soil water consumption.In this study,we monitored the jujube plots with control(CK),light(C1),medium(C2)and high(C3)pruning intensities during the jujube growing period of 2012-2015 to explore the effect of pruning intensity on soil moisture and water use efficiency(WUE)of jujube plantations in the hilly Loess Plateau Region.The results showed that pruning is an effective method for soil water conservation in jujube plantations.Soil moisture increased with increasing pruning intensity during the jujube growing period of 2012-2015.C1,C2 and C3 pruning intensities increased soil water storage by 6.1-18.3,14.4-40.0 and 24.3-63.3 mm,respectively,compared to CK pruning intensity.Pruning promoted soil moisture infiltration to deeper soil layer.Soil moisture infiltrated to soil depths of 240,280 and>300 cm under C3 pruning intensity,220,260 and 260 cm under C2 pruning intensity,200,240 and 220 cm under C1 pruning intensity,and 180,200 and 160 cm under CK pruning intensity in 2013,2014 and 2015,respectively.Soil water deficit was alleviated by higher pruning intensity.In 2013-2015,soil water change was positive under C2(6.4 mm)and C3(26.8 mm)pruning intensities but negative under C1(-20.5 mm)and CK(-40.6 mm)pruning intensities.Moreover,pruning significantly improved fresh fruit yield and WUE of jujube plants.Fresh fruit yields were highest under C1 pruning intensity with the values of 6897.1-13,059.3 kg/hm^2,which were 2758.4-4712.8,385.7-1432.1 and 802.8-2331.5 kg/hm2 higher than those under CK,C2,and C3 pruning intensities during the jujube growing period of 2012-2015,respectively.However,C3 pruning intensity had the highest WUE values of 2.92-3.13 kg/m3,which were 1.6-2.0,1.1-1.2 and 1.0-1.1 times greater than those under CK,C1 and C2 pruning intensities,respectively.Therefore,C3 pruning intensity is recommended to jujube plantations for its economic and ecological benefits.These results provide an alternative strategy to mitigate soil desiccation in jujube plantations in the hilly Loess Plateau Region,which is critical for sustainable cultivation of economic forest trees in this region.展开更多
The effect of first thinning and pruning on height, diameter at breast height (DBH), and volume growth was studied in individual trees of Pinus patula Schiede and Deppe in Chongoni Plantation, using four plots for t...The effect of first thinning and pruning on height, diameter at breast height (DBH), and volume growth was studied in individual trees of Pinus patula Schiede and Deppe in Chongoni Plantation, using four plots for thinning trials. Each of the plots was 0.5 ha and subjected to one of the fol- lowing silvicultural treatments: first thinning and pruning, first thinning and no pruning, pruning and no thinning, and control (no pruning and no thinning). The silvicultural treatments were randomized in four replicates. Fourteen years after planting, the following parameters were measured including total height, DBH, and volume. The highest DBH and volume growth was observed in thinning and pruning, while the highest growth in height was observed where there was pruning and no thinning. Clearly, both thinning and pruning are an important manage- ment option in pine species plantations in Malawi to maximize the increase in volume productivity.展开更多
With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved ...With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved pruning algorithm for the GM-PHD filter, which utilizes not only the Gaussian components’ means and covariance, but their weights as a new criterion to improve the estimate accuracy of the conventional pruning algorithm for tracking very closely proximity targets. Moreover, it solves the end-less while-loop problem without the need of a second merging step. Simulation results show that this improved algorithm is easier to implement and more robust than the formal ones.展开更多
Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticu...Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticum aestivum). The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots (1.06 and 0.94 mmol g-1 s-1, respectively). The soil water content (SWC) at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants (61.1-44.6% field water capacity) than for intact root plants (57.9-46.1% field water capacity). At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield (F PS II ), the maximum photochemical efficiency of PS II (F v /F m ), coefficient of photochemical quenching (qP), and coefficient of non-photochemical quenching (NPQ), in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency (WUE) than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.展开更多
A litterbag experiment of 12 weeks was conducted to study nitrogenmineralization process of prunings of six nitrogen-fixing hedgerowspecies in a dry valley of the Jinsha River. Prunigns wereincorporated into soil or u...A litterbag experiment of 12 weeks was conducted to study nitrogenmineralization process of prunings of six nitrogen-fixing hedgerowspecies in a dry valley of the Jinsha River. Prunigns wereincorporated into soil or used as mulch. The results indicated thatpruning N of the six hedgerow species was mineralized fast in thefirst week and then decreased slowly in the rest of the study period.When prunings were incorporated into soil, the amount of nitrogenmineralized by the end of the first week accounted for 69.9/100,58.2/100, 54.5/100, 43.0/100, 29.6/100 and 20.6/100 of the total N inprungins of Desmodium rensonii, Tephrosia candida, Leucaenaleucoephala, Albizia yunnanensis, Acacia dealbata, and Acaciamearnsii, respectively.展开更多
As the solutions of the least squares support vector regression machine (LS-SVRM) are not sparse, it leads to slow prediction speed and limits its applications. The defects of the ex- isting adaptive pruning algorit...As the solutions of the least squares support vector regression machine (LS-SVRM) are not sparse, it leads to slow prediction speed and limits its applications. The defects of the ex- isting adaptive pruning algorithm for LS-SVRM are that the training speed is slow, and the generalization performance is not satis- factory, especially for large scale problems. Hence an improved algorithm is proposed. In order to accelerate the training speed, the pruned data point and fast leave-one-out error are employed to validate the temporary model obtained after decremental learning. The novel objective function in the termination condition which in- volves the whole constraints generated by all training data points and three pruning strategies are employed to improve the generali- zation performance. The effectiveness of the proposed algorithm is tested on six benchmark datasets. The sparse LS-SVRM model has a faster training speed and better generalization performance.展开更多
基金supported by the National Natural Science Foundation of ChinaNo.32200778(to QC)+5 种基金the Natural Science Foundation of Jiangsu ProvinceNo.BK20220494(to QC)Suzhou Medical and Health Technology Innovation ProjectNo.SKY2022107(to QC)a grant from the Clinical Research Center of Neurological Disease in The Second Affiliated Hospital of Soochow UniversityNos.ND2022A04(to QC)and ND2023B06(to JS)。
文摘Microglia are the main non-neuronal cells in the central nervous system that have important roles in brain development and functional connectivity of neural circuits.In brain physiology,highly dynamic microglial processes are facilitated to sense the surrounding environment and stimuli.Once the brain switches its functional states,microglia are recruited to specific sites to exert their immune functions,including the release of cytokines and phagocytosis of cellular debris.The crosstalk of microglia between neurons,neural stem cells,endothelial cells,oligodendrocytes,and astrocytes contributes to their functions in synapse pruning,neurogenesis,vascularization,myelination,and blood-brain barrier permeability.In this review,we highlight the neuron-derived“find-me,”“eat-me,”and“don't eat-me”molecular signals that drive microglia in response to changes in neuronal activity for synapse refinement during brain development.This review reveals the molecular mechanism of neuron-microglia interaction in synaptic pruning and presents novel ideas for the synaptic pruning of microglia in disease,thereby providing important clues for discovery of target drugs and development of nervous system disease treatment methods targeting synaptic dysfunction.
基金supported by National Natural Science Foundation of China(Nos.61902158 and 62202210).
文摘The rapidly advancing Convolutional Neural Networks(CNNs)have brought about a paradigm shift in various computer vision tasks,while also garnering increasing interest and application in sensor-based Human Activity Recognition(HAR)efforts.However,the significant computational demands and memory requirements hinder the practical deployment of deep networks in resource-constrained systems.This paper introduces a novel network pruning method based on the energy spectral density of data in the frequency domain,which reduces the model’s depth and accelerates activity inference.Unlike traditional pruning methods that focus on the spatial domain and the importance of filters,this method converts sensor data,such as HAR data,to the frequency domain for analysis.It emphasizes the low-frequency components by calculating their energy spectral density values.Subsequently,filters that meet the predefined thresholds are retained,and redundant filters are removed,leading to a significant reduction in model size without compromising performance or incurring additional computational costs.Notably,the proposed algorithm’s effectiveness is empirically validated on a standard five-layer CNNs backbone architecture.The computational feasibility and data sensitivity of the proposed scheme are thoroughly examined.Impressively,the classification accuracy on three benchmark HAR datasets UCI-HAR,WISDM,and PAMAP2 reaches 96.20%,98.40%,and 92.38%,respectively.Concurrently,our strategy achieves a reduction in Floating Point Operations(FLOPs)by 90.73%,93.70%,and 90.74%,respectively,along with a corresponding decrease in memory consumption by 90.53%,93.43%,and 90.05%.
文摘Prunusmumehas high ornamental value,and its maintenance and management should be more meticulous,with pruning being an important task.Pruning can make P.mume more robust,reduce the occurrence of diseases and pests,maintain a good shape,and promote more flowering,further improving its ornamental value.The difficulty of pruning lies in flexibly adopting suitable pruning methods according to the time of the tree,which requires understanding the impact of pruning operations on the growth and flowering of P.mume,as well as some techniques in pruning operations.This paper introduces the botanical characteristics of P.mume,common pruning methods and achievable effects of P.mume,and suitable time for using various methods,and analyzes the possible consequences and reasons of some incorrect operations.Moreover,corresponding correct practices are provided,which can provide reference for standardized pruning of P.mume,thereby reducing or avoiding losses caused by improper operation.
文摘To determine the correlations between the tree structuresof Fuji apple with different pruning modes and each factor, the data about 3 tree structures which were free spindle short shoot, free spindle long shoot and slenderspindle short shoot in Xingtang County of Hebai Province were investigated, then by SPSS anal- ysis, the correlations between the taperingness and each growth factor of inserted small branch were compared. The results showed that the taperingness of central trunk of free spindle dwarf-shoot Fuji apple treeshad negative correlations with each factor of inserted small branch, while the taperingness of central trunk of free spin- dle long-shoot Fuji apple treeshad positive correlations with each factor of inserted small branch, the taperingness of central trunk of slenderspindle short-shootFuji ap- ple treeshad negative correlation with total thickness of inserted small branch, but had positive correlations with other factors. This study can provide a scientifictheo- retical basis for the pruning technology of high-density planting trees grafting by dwarfing self-rooted rootstock.
基金Supported by the China Agriculture Research System(CARS-28)the Project of the Science and Technology Department of Hebei Province(11220104D-1)~~
文摘To determine the correlation between the stem taperingness and central shaft by free spindle pruning mode on different apple cultivars, the central shaft growth data of three cultivars of free spindle short shoot "Fuji", free spindle long shoot "Fuji", free spindle "Huaguan" were investigated in Xingtang County of Hebei Province by SPSS analysis. The results showed that the stem taperingness on free spindle short shoot "Fuji" was in negative correlation with central shaft, but the correlation was not significant. While the stem taperingness on free spindle long shoot "Fuji" was in positive correlation with central shaft, but the correlation was not significant either. The stern taperingness on free spindle "Huaguan" was in negative correlation with central shaft, and the correlation between the stem taperingness and the central shaft total length was significant at the level of 0.01. The results.provided scientific theoretical basis for guiding the dwarfing rootstocks close planting apple tree pruning technology.
基金Supported by National Key Technology R&D Program(2014BAD05B04)The Expert Program of Cultivation Post for Hunan Vegetable Industry Technology System基金项目国家科技支撑课题(2014BAD-05B04)~~
文摘In the Yangtze River region, thepepper long-season cultivation needs oversummer pruning. Inorder to study the effects of different pruning treatments on growth of over-summer grown pepper, three differentpruning treatments were applied to pepper seedlings, such as treatment one(re-growth pruning), treatment two(four stems) and treatment three(multi-stem pruning) with no pruning as control(CK).The results showed that themulti-stem pruning treatment enabling the plant to maintain the good plant type for high yield and reduce thevirus disease to improve the marketability of pepper fruits, compared with the other two pruning treatments;andthe yield and economic benefit were increased by 15.8% and 19%, compared with the control, respectively. Ingeneral the multi-stem pruning was the best for over-summer pepper cultivation.
基金supported by the China National Support Program(2015BAC01B03)the Shaanxi Co-ordination Program(2016KTZDNY0105)the National Key Research and Development Program of China(2016YED0300201)
文摘Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized as a water-saving method that can reduces soil water consumption.In this study,we monitored the jujube plots with control(CK),light(C1),medium(C2)and high(C3)pruning intensities during the jujube growing period of 2012-2015 to explore the effect of pruning intensity on soil moisture and water use efficiency(WUE)of jujube plantations in the hilly Loess Plateau Region.The results showed that pruning is an effective method for soil water conservation in jujube plantations.Soil moisture increased with increasing pruning intensity during the jujube growing period of 2012-2015.C1,C2 and C3 pruning intensities increased soil water storage by 6.1-18.3,14.4-40.0 and 24.3-63.3 mm,respectively,compared to CK pruning intensity.Pruning promoted soil moisture infiltration to deeper soil layer.Soil moisture infiltrated to soil depths of 240,280 and>300 cm under C3 pruning intensity,220,260 and 260 cm under C2 pruning intensity,200,240 and 220 cm under C1 pruning intensity,and 180,200 and 160 cm under CK pruning intensity in 2013,2014 and 2015,respectively.Soil water deficit was alleviated by higher pruning intensity.In 2013-2015,soil water change was positive under C2(6.4 mm)and C3(26.8 mm)pruning intensities but negative under C1(-20.5 mm)and CK(-40.6 mm)pruning intensities.Moreover,pruning significantly improved fresh fruit yield and WUE of jujube plants.Fresh fruit yields were highest under C1 pruning intensity with the values of 6897.1-13,059.3 kg/hm^2,which were 2758.4-4712.8,385.7-1432.1 and 802.8-2331.5 kg/hm2 higher than those under CK,C2,and C3 pruning intensities during the jujube growing period of 2012-2015,respectively.However,C3 pruning intensity had the highest WUE values of 2.92-3.13 kg/m3,which were 1.6-2.0,1.1-1.2 and 1.0-1.1 times greater than those under CK,C1 and C2 pruning intensities,respectively.Therefore,C3 pruning intensity is recommended to jujube plantations for its economic and ecological benefits.These results provide an alternative strategy to mitigate soil desiccation in jujube plantations in the hilly Loess Plateau Region,which is critical for sustainable cultivation of economic forest trees in this region.
文摘The effect of first thinning and pruning on height, diameter at breast height (DBH), and volume growth was studied in individual trees of Pinus patula Schiede and Deppe in Chongoni Plantation, using four plots for thinning trials. Each of the plots was 0.5 ha and subjected to one of the fol- lowing silvicultural treatments: first thinning and pruning, first thinning and no pruning, pruning and no thinning, and control (no pruning and no thinning). The silvicultural treatments were randomized in four replicates. Fourteen years after planting, the following parameters were measured including total height, DBH, and volume. The highest DBH and volume growth was observed in thinning and pruning, while the highest growth in height was observed where there was pruning and no thinning. Clearly, both thinning and pruning are an important manage- ment option in pine species plantations in Malawi to maximize the increase in volume productivity.
基金supported by the National Natural Science Foundation of China(61703228)
文摘With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved pruning algorithm for the GM-PHD filter, which utilizes not only the Gaussian components’ means and covariance, but their weights as a new criterion to improve the estimate accuracy of the conventional pruning algorithm for tracking very closely proximity targets. Moreover, it solves the end-less while-loop problem without the need of a second merging step. Simulation results show that this improved algorithm is easier to implement and more robust than the formal ones.
基金supported by the Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,China(10501-1201)the Key Technologies R&D Program of China during the 11th Five-Year Plan period(2012BAD14B08)the Innovation Team Program,Ministry of Education of China
文摘Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticum aestivum). The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots (1.06 and 0.94 mmol g-1 s-1, respectively). The soil water content (SWC) at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants (61.1-44.6% field water capacity) than for intact root plants (57.9-46.1% field water capacity). At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield (F PS II ), the maximum photochemical efficiency of PS II (F v /F m ), coefficient of photochemical quenching (qP), and coefficient of non-photochemical quenching (NPQ), in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency (WUE) than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.
基金Project supported jointly by the Chengdu Di Ao Science Foundation and the Sichuan Provincial Science Foundation for Young Scient
文摘A litterbag experiment of 12 weeks was conducted to study nitrogenmineralization process of prunings of six nitrogen-fixing hedgerowspecies in a dry valley of the Jinsha River. Prunigns wereincorporated into soil or used as mulch. The results indicated thatpruning N of the six hedgerow species was mineralized fast in thefirst week and then decreased slowly in the rest of the study period.When prunings were incorporated into soil, the amount of nitrogenmineralized by the end of the first week accounted for 69.9/100,58.2/100, 54.5/100, 43.0/100, 29.6/100 and 20.6/100 of the total N inprungins of Desmodium rensonii, Tephrosia candida, Leucaenaleucoephala, Albizia yunnanensis, Acacia dealbata, and Acaciamearnsii, respectively.
基金supported by the National Natural Science Foundation of China (61074127)
文摘As the solutions of the least squares support vector regression machine (LS-SVRM) are not sparse, it leads to slow prediction speed and limits its applications. The defects of the ex- isting adaptive pruning algorithm for LS-SVRM are that the training speed is slow, and the generalization performance is not satis- factory, especially for large scale problems. Hence an improved algorithm is proposed. In order to accelerate the training speed, the pruned data point and fast leave-one-out error are employed to validate the temporary model obtained after decremental learning. The novel objective function in the termination condition which in- volves the whole constraints generated by all training data points and three pruning strategies are employed to improve the generali- zation performance. The effectiveness of the proposed algorithm is tested on six benchmark datasets. The sparse LS-SVRM model has a faster training speed and better generalization performance.